New artificial reef to be part of Petone to Ngauranga pathway project

Tuesday, 20 February 2024

An artificial reef is being built as part of the Petone to Ngauranga shared path and seawall.

An artificial reef that will be home to octopus, crabs, crayfish and starfish is being created in Wellington Harbour as part of the Petone to Ngauranga walking and cycling pathway.

“This will be the first project of its kind on this scale in New Zealand,” said NZ Transport Agency Waka Kotahi’s Jetesh Bhula.

Fifty four concrete ‘pyramids’ will be submerged in clusters of three over five hectares on the western side of the harbour. They should mirror the natural rocky reef that’s been lost during the building of the walking and cycling link.

“Experts have designed them to generate water flows that encourage the growth of plant life, algae, shellfish, snails and kina.”

An artist’s impression of the new reef supporting marine life. Fifty-four engineered pyramids will be submerged off Wellington Harbour’s western edge at the northern end of the pathway project.

Restoring and protecting the environment had always been a key component of the pathway project, of which the reef was an “essential” part.

The pyramids have been designed to help generate water flows that encourage the growth of plant life, algae, shellfish, snails and kina.

“The future health and wellbeing of the harbour is just as important as the shared pathway being built.”

Construction on the $312m Petone to Ngauranga shared path and seawall started in March last year. Work on the reef will start in May.

Working with iwi mana whenua, Taranaki Whānui ki te Upoko o te Ika and Ngāti Toa, the reef’s progress will be monitored to ensure it provides a thriving habitat with more fish and well-developed shellfish and plant populations.

Work on the reef is expected to start in May.

The Petone to Ngauranga shared pathway is part of a bigger project, known as Te Ara Tupua, which will eventually make it possible to safely cycle/walk from Wellington to Eastbourne.

NZTA estimates that 2100 cyclists will use the path daily by 2030, as well as 360 runners or walkers and 290 trips on escooters.

More about the project

The shared path is 4.5km long with a 5m sealed surface on the seaward side of the railway line. It is expected to be finished by 2026.
Sloping embankments (known as revetments) built of either boulders or concrete armour units, will protect the shared path, road and rail line from erosion by waves. The design allows for it to be built on to in the future to adapt to climate change and the rising harbour level.
The project is part of a bigger project, known as Te Ara Tupua, which will eventually make it possible to safely cycle/walk from Wellington to Eastbourne.